A Closer Look At Arthroscopy For Ankle Fractures And Post-Fracture Defects

Arthroscopy is an expedient tool in the management of intra-articular fractures of the ankle and post-fracture articular defects. It provides the surgeon the ability to anatomically reduce a fracture under direct visualization with minimal intervention. It also enables the surgeon to address any articular injury primarily.

The AO philosophy has remained consistent and clear. When it comes to patients with displaced, unstable ankle fractures and related problems, we strive for operative anatomic reduction and stabilization designed to bring an early return to mobility and function. Is this enough? Can one treat the injured articular surface in conjunction with osseous reduction and fixation?

New evidence is shedding light on the fact that almost 80 percent of malleolar fractures have a concomitant chondral or osteochondral defect.1,2 Historically, there has been significant attention in the literature on the management of chronic osteochondral lesions of the tibiotalar joint and their treatment outcomes.

As surgeons who manage patients with this pathology, we know osteochondral lesions of the talus are often missed and treatment can be delayed for months and often years. If we are to subject the patient to an operation for the ankle fracture, why not evaluate and primarily treat the associated intra-articular pathology that is known to be a cause of chronic ankle dysfunction?

The established AO principles of anatomic reduction with internal fixation are well known to the foot and ankle surgeon. Intra-articular incongruity is one of the main reasons fractures are surgically addressed. The tibia takes approximately five-sixths of the load at the ankle joint and patients tolerate articular malreductions poorly.

With certain fracture types and patterns, accurate anatomic reduction can be difficult to obtain without significant soft tissue disruption. Accomplishing this anatomic reduction by the least invasive yet still effective means is a matter of increasing concern. This is especially true given the complications that can ensue, especially in the geriatric and diabetic patient population. Arthroscopic assisted fracture reduction can provide a less invasive operative reduction of the fracture and respects the soft tissue envelope.

Fractures about the ankle that are amenable to arthroscopic assisted reduction and fixation include:

What about the case of the patient who has persistent pain several months after the fracture has healed? This persistent pain can be attributed to intra-articular pathology as previously discussed. The patient who was treated operatively or non-operatively can have fibular malunion. Chronic syndesmotic instability can also be the source of ongoing pain. Arthroscopy in conjunction with intra-articular debridement and/ or osseous realignment procedures can benefit all of these patients.

Utsugi and colleagues published a paper on 40 patients who underwent ankle arthroscopy one year after the index procedure.3 Almost a third of the patients required a functional derotation of the ankle joint. Arthroscopy showed articular cartilage damage in 33 percent of patients and arthrofibrosis in 73 percent. Furthermore, 89 percent of patients with functional derotation of the fibula and combined arthroscopic debridement showed improved articular function.

Keys To Initial Assessment And Patient Management

One should obtain standard radiographic views of the ankle for the initial assessment of the fracture pattern. Computed tomography (CT) of fractures is sometimes warranted when extensive comminution or intra-articular involvement is present. This aids in preoperative planning of fracture surgery. If there is high fibular tenderness, obtain a tibia-fibula series in order to include the ankle and knee joints. Obtain foot X-rays when the clinical exam warrants.

With the patient hemodynamically stable, perform closed reduction of the fractures and relocation of any joint subluxation or dislocation. Apply a layered compressive dressing and splint, and instruct the patient to elevate the injured limb. One may use two surgical windows to fix the injured extremity. The early period is within six hours after the injury whereas the late period is between six to 12 days.

It is unwise to make incisions in between the six-hour and six-day window as this increases the likelihood of postoperative wound problems.5 The surgeon has to respect this principle of allowing the tissue envelope to “settle” if one is to perform arthroscopic assisted reduction as soft tissue extravasation of ingress fluid from the arthroscopy procedure can further increase the likelihood of wound problems.

Assessing The Benefits And Contraindications Of Arthroscopic Reduction

There are many advantages to arthroscopic assisted reduction. These advantages include: minimal surgical intervention; direct visualization of fracture reduction; comprehensive intra-articular evaluation; and acute treatment of chondral and osteochondral injuries.

The contraindications to performing arthroscopic assisted reduction include: a grossly compromised soft tissue envelope; excessive soft tissue edema with or without blisters; and open fractures.

Surgeons can use large (4 mm) or small joint (2.7 mm) arthroscopes. Utilize standard anteromedial and anterolateral portals. One can establish a posterolateral portal for posterior talar lesions or posterior malleolar fractures.

The authors recommend avoiding arthroscopic pumps as a rule. Gravity inflow is preferred. Separate inflow and outflow portals help with distention visualization. Pumps require a three-in-one cannula system, one for inflow, one for outflow and another to determine intra-articular pressure. If the cannula inadvertently slips into the subcutaneous space and no outflow is measured, the pump can dramatically increase inflow pressure.

Excessive fluid extravasation can potentially cause compartment ischemia and it has been documented. Gravity inflow avoids this potential complication. We recommend using two 3- to 4-L bags of lactated Ringer’s solution at about three feet above the table with large diameter, high flow Y-tubing.

With most fracture patterns, one can adequately evaluate the ankle joint without distraction. The unstable ankle mortise allows for easier passage of instruments than in elective ankle arthroscopy. However, with posterior ankle pathology or difficult fracture reductions as one may see with subacute fractures, ankle distraction is warranted.

Takao described a Kerlix roll technique for distraction.5 We have modified this somewhat by using industry fabricated noninvasive straps and a 4-inch gauze roll. This technique facilitates efficient intraoperative set-up and ensures surgeon flexibility in the use of ankle distraction during the arthroscopic portion of the procedure.

Case Study One: When A Skateboarder Has A Medial Malleolus Fracture

A 15-year-old male with closed physes sustained a closed bimalleolar injury while skateboarding. Radiographs demonstrated a medial malleolar pronation abduction (PAB) type of injury and an incomplete fracture of the lateral malleolus.

The surgeon made standard anteromedial and anterolateral portals. The surgeon debrided the fracture site and curetted the site clear of hematoma and debris. After evacuating the debris and hematoma, one could visualize the fracture line.

One could then reduce the fracture either with reduction forceps and an arthroscopic check, or percutaneously secure the site with K-wires from the cannulated screw set. Using the wire technique, insert wires from the tip of the medial malleolus and advance the wires just proximal to the fracture line. One can then use the wires to “joystick” the fragments into place with arthroscopic visualization to verify reduction. Once you have achieved adequate reduction, you can advance the wires across the fracture site and insert screws if the wire position is optimal.

A 33-year-old male slipped on some stairs and sustained a closed bimalleolar fracture. At first glance, the plain radiographs demonstrate a fairly typical bimalleolar fracture. One might question whether arthroscopy is necessary.

Intraoperatively, the surgeon noted a large lateral osteochondral fragment. We typically perform a 10-minute cursory arthroscopy prior to open reduction internal fixation (ORIF), given the high incidence of chondral and osteochondral lesions.

Ferkel identified osteochondral lesions in almost 80 percent of the ankles that underwent ankle arthroscopy and operative fixation in conjunction with an acute ankle fractures.1

Recently, Leontaritis and colleagues looked at 283 ankle fractures that had ORIF and underwent ankle arthroscopy.2 The researchers classified the ankle injuries according to the Lauge-Hansen criteria. Seventy-three percent had chondral lesions. Articular injuries were common in the more severe ankle fracture patterns. This included the pronation external rotation (PER) injuries and supination external-rotation (SER) type IV patterns.

Case Study Three: When A Pediatric Patient Has A Tillaux Fracture With Displacement

A 12-year-old female sustained a closed fracture with a twisting injury while playing basketball. Her mortise radiographs demonstrated a Tillaux fracture with a 3 to 4 mm displacement. After surgeons removed the hematoma and debris, they could clearly visualize the fracture gap. They reduced the fracture and stabilized it with a reduction clamp utilizing a small anterolateral incision over the distal tibia. They checked the reduction with the arthroscope and manipulated the fragment to obtain articular congruity. Fixation can be with either cannulated or solid screws. For this patient, surgeons used a 3.5 mm solid lag screw.

In 1898, John Poland performed an extensive study of epiphyseal separations about the ankle. He noted that ankle injuries in children differed from those in adults in three important ways.6

• The growth plate forms a plane of weakness directing fracture lines in patterns different from those in adults.
• Ligaments are stronger than bone so ligamentous injuries are less common in children.
• Certain injures will affect growth.

Remember that nearly 40 percent of physeal injuries reported in children are ankle fractures. More than half of these ankle fractures in children occur during sports activities.7

A Tillaux injury almost always occurs in the adolescent within a year of complete closure of the distal tibial physis. This injury is a Salter-Harris type III fracture in which the lateral portion of the distal tibial physis is injured. The central and medial aspects of the tibial physis have closed, leaving the anterolateral aspect open and vulnerable to injury. An external rotation force on the foot may avulse the anterolateral quadrant of the tibial physis, which is bound to the fibula by the strong anterior tibiofibular ligament. This may result in a rectangular or pie-shaped fragment breaking off the distal tibial epiphysis.

Case Study Four: Treating A Triplane Fracture In A High School Football Player

A healthy 15-year-old male sustained an injury in a high school football game. A CT scan confirmed a three-part intra-articular fracture. The coronal view noted no articular step-off but identified a 3 mm displacement. Three-dimensional CT reconstruction provided a very clear understanding of the fracture pattern.

In order to restore articular congruity, the surgeon performed arthroscopic assisted fracture reduction. There was no evidence of any articular step-off and apposition of the fracture fragments. The surgeon fixated the fragments with cortical lag screws directed anterior to posterior and medial to lateral.

The tibial triplane fracture is a complex fracture defined by sagittal, transverse and coronal components that courses in part along and in part through the physis, and enters the ankle joint. Classically, this fracture appears as a Sanders type III injury on the AP projection and as a type II injury on the lateral view.8,9 A CT scan is an invaluable tool in defining the fracture configuration and the amount of intra-articular displacement.

Most classifications are based on three factors: medial or lateral location, the number of parts, and whether it is an intra- or extra-articular fracture. Fractures of the fibula may be present in conjunction with any triplane fracture. Three-part fractures have a propensity for intra-articular incongruity. These type of injuries leave a posterior metaphyseal-epiphyseal fragment that behaves like a Salter-Harris IV fracture. This fragment may migrate proximally and leave an articular step-off in the joint surface.

Case Study Five: When Chronic Syndesmotic Instability Occurs

A 59-year-old male sustained a Grade II open trimalleolar ankle fracture while trying to apprehend two men who attempted to steal his car. The open injury also resulted in extensive capsular disruption. After malleolar reduction, the tibiotalar joint had anterior subluxation so surgeons inserted smooth transcutaneous Steinmann pins for further stabilization. The fractures and skin envelope progressed to healing in a fairly uneventful fashion with the ankle mortise appearing relatively well preserved. Surgeons removed the syndesmotic screws four months after the index procedure.

The patient was then lost to follow-up. He reappeared roughly seven months after the screw removal, complaining of a swollen ankle. Radiographs demonstrated an unstable ankle syndesmosis that was clearly widened and a talus in valgus malposition.

Looking at the reconstructive options, surgeons decided to attempt a joint salvage procedure as opposed to an ankle arthrodesis. The syndesmosis underwent bone grafts and surgeons performed a distal syndesmotic fusion. After obtaining a congruent joint, surgeons performed arthroscopy. The joint showed significant articular damage but at two years postoperatively, the patient is still functioning well.

In Summary

Arthroscopy is a wonderful tool in the management of certain intra-articular fractures of the ankle. It assists in attaining anatomical reduction while minimizing disruption of the soft tissue envelope. Arthroscopy also enables the surgeon to debride the joint and address any articular defects primarily. This approach may offer the patient distinctive advantages in the future. Arthroscopy is also an excellent adjunct in the treatment of post-traumatic ankle pathology such as osseous malunion, synovitis, arthrofibrosis and chronic syndesmotic instability.

Further clinical studies are needed to accurately determine clinical benefit but the authors have already noted clinical benefit in their patients with the use of arthroscopy in ankle fracture management.

Dr. Hamilton is affiliated with the Department of Orthopedics and Podiatric Surgery of Kaiser Permanente in Antioch, Calif. He is a Fellow of the American College of Foot and Ankle Surgeons.

Dr. Sautter is affiliated with the Department of Orthopedics and Podiatric Surgery of Kaiser Permanente in Antioch, Calif. He is an Associate of the American College of Foot and Ankle Surgeons.

Dr. Burks is a Fellow of the American College of Foot and Ankle Surgeons, and is board-certified in foot and ankle surgery. He is in private practice in Little Rock, Ark.

For further reading, see “Current Concepts In Ankle Arthroscopy” in the December 2007 issue of Podiatry Today or “A Pertinent Guide To Basic Ankle Arthroscopy” in the November 2003 issue.